An egress router is a Label Switch Router

Label Switch Router

A label switch router , is a type of a router located in the middle of a Multiprotocol Label Switching network...

 that is an end point (drain) for a given Label Switched Path

Label Switched Path

In MPLS networking, a Label Switched Path is a path through an MPLS network, set up by a signaling protocol such as LDP, RSVP-TE, BGP or CR-LDP. The path is set up based on criteria in the forwarding equivalence class ....

 (LSP). An egress router may be an ingress router

Ingress router

An "ingress router" is a Label Switch Router that is a starting point for a given Label Switched Path . An ingress router may be an egress router or an intermediate router for any other LSP. Hence the role of ingress and egress routers is LSP specific...

 or an intermediate router for any other LSP(s). Hence the role of egress and ingress routers is LSP specific. Usually, the MPLS

Multiprotocol Label Switching

Multiprotocol Label Switching is a mechanism in high-performance telecommunications networks that directs data from one network node to the next based on short path labels rather than long network addresses, avoiding complex lookups in a routing table. The labels identify virtual links between...

label is attached with an IP packet at the ingress router and removed at the egress router, whereas label swapping is performed on the intermediate routers.